What causes milky white cloudy aquarium water?

Guppies in the aquarium
(Last Updated On: March 12, 2017)

Milky white cloudy aquarium water is often just temporary. Poorly rinsed gravel in a new aquarium can cause white cloudiness. Restarting the filters after a shutdown can cause debris and tiny air bubbles to create a white haze. Adding supplements such as bacteria, pH adjusters, or calcium can also create a temporary milky white haze in the water.

All of these sources of white cloudiness are usually just temporary, lasting only a few hours to a few days.

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If the cloudiness persists, it is likely caused by bacteria growing at rates that turn the aquarium water milky white. This kind of fast bacteria growth is usually the result of excessive organic waste within the fish tank.

Causes for milky white aquarium water:

  • The aquarium is new and bacteria are settling. These nitrifying bacteria are needed as they make the water safe for fish by converting highly toxic ammonia to the less toxic nitrate (see ‘The Nitrogen Cycle‘ for more info). During the initial stages of a new aquarium setup bacteria and waste levels will not be balanced, often resulting in milky white cloudy aquarium water.
  • The bacteria colony has been disturbed by environmental changes i.e pH or temperature fluctuations or by anti-bacterial medication. Re-establishing of the colonies can cause the water to turn white.
  • Larger additions of fish or livestock can cause bacterial colonies to multiply every 20 minutes in an effort to convert the additional organic waste being produced. The re-balancing of the biological balance will require some time. Again the result can be milky white cloudiness.

With growing bacteria in the aquarium, oxygen can be depleted. To solve the problem, correct any of the above mentioned causes. Most common are the addition of livestock which causes dangerous spikes on organic waste.

Algone will clear and prevent cloudy water by removing organic and inorganic waste. Algone will also minimize ammonia and nitrite spikes and lessen their highly toxic effect on fish and other livestock.

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92 thoughts on “What causes milky white cloudy aquarium water?

  1. Valerie Martin says:

    My tank water is lime green and the water is making my bedroom smell really bad. Its the water in the tank what should I do

    • Scott @ Algone
      Scott @ Algone says:

      This is quite vague, so in a nutshell… make sure you are:

      1. running an adequately sized aquarium filter
      2. performing regular water changes
      3. not overcrowding the aquarium with too many fish
      4. not overfeeding your fish

      The green water is likely free-floating algae. Algae thrives in high nutrient water, particularly high nitrates. Nitrates are the result of decaying waste in the fish tank… uneaten fish food, fish poop, etc… Accumulating nitrates are due to too much waste entering the tank, a lack of maintenance, or both. Good aquarium maintenance practices are essential for a healthy aquarium, as are sensible stocking levels and feeding schedules.

  2. Mark P says:

    We moved my fish tank downstairs and cleaned it out and everything got a new filter rinsed the rocks and everything and then the water got white and cloudy so we cleaned it again and it happened again. Not sure what’s happening

    • Thilo
      Thilo says:

      That would be a bacteria bloom. Bacteria, which make the water safe for the fish, settle anywhere in the aquarium. The filter is a preferred location because of, among others, the higher oxygen supply. Replacing the filter will also displace the bacteria. Cleaning has the same effect. If you see a slimy area, that is the protective coat of the colony. Just rinse the filter if it needs cleaned.
      Adjust the filter outlet, or lower the water level to the point where the filter outlet creates waves. This will ensure proper oxygen levels. You can wait this out, or use Algone to speed up the process.

  3. Heather says:

    Hello I have a five gallon tank that I am setting up for a betta. I thought I washed everything thoroughly before putting my water in with my betta water conditioner. It got cloudy about two days in, and now has been cloudy for 3 days. I have a filter, heater, gravel, and a digital thermometer in it so far, haven’t put decorations in it yet. What should I do? Should I wait it out or just restart?

  4. Krystian Borja says:

    Hi i have a 15 gallon aquarium it has not been cycled and i added new fish. The fish for what i see is ok and it is eating. But the water is cloudy. What should i do?

    • Scott @ Algone
      Scott @ Algone says:

      Just feed sparingly and perform a modest water change of about 15% of water every 5 – 7 days. This should keep nutrients lower and ease the effects of the aquarium break-in on your fish. Once sufficient beneficial bacteria are established, the tank should clear up on its own. Otherwise, consider an aquarium water clarifier such as Algone.

  5. Guy Hanna says:

    I have a brand new 65 gallon Aquarium. I rinsed off my gravel and set everything up for my fish. It is still foggy white, Is it my gravel or just that it is new?

    • Scott @ Algone
      Scott @ Algone says:

      Yes, it’s likely just from the gravel. If it persists for more the a couple of days, it may be a bacterial bloom. One post below, Thilo explains this to another aquarium keeper as follows:

      Bacteria that grow ahead of the beneficial bacteria can grow at speeds that turns the water cloudy. This is referred to as a bacteria bloom. No danger for as long as the aquarium is well oxygenated, as most are just by water surface movement.
      Bacteria blooms can occur if, the aquarium is newly set up, fish have been added, the bacteria got disturbed by either to intense cleaning, filter changes, changes in live stock, or medication (antibiotics). You can use Algone to speed up the process of clearing the water, or wait it out.

  6. Virginia says:

    I have a 54 gallon tank. It’s been set up for bout 3months now. I decided to do a GLOW FISH TANK. It was touch and go for awhile …getting the water just right. Anyhow I have been able to add fish over time but now my water is very cloudy…took the water to have it checked and all was good except the ph was a little acidic but said not dangerous so we put the ph adjuster in it…please help ,,,do I just let it run it’s course….

    • Thilo
      Thilo says:

      Bacteria that grow ahead of the beneficial bacteria can grow at speeds that turns the water cloudy. This is referred to as a bacteria bloom. No danger for as long as the aquarium is well oxygenated, as most are just by water surface movement.
      Bacteria blooms can occur if, the aquarium is newly set up, fish have been added, the bacteria got disturbed by either to intense cleaning, filter changes, changes in live stock, or medication (antibiotics). You can use Algone to speed up the process of clearing the water, or wait it out.

  7. Paulina says:

    I have a 30 gallon tank i recently did my yearly full clean of the tank and cleaned the rocks its murky white, and its getting worse. The water is more white after a fewe days.

    • Scott @ Algone
      Scott @ Algone says:

      This sounds like a bacterial bloom, which is not uncommon for newly setup aquariums. Since you did a full cleaning, your tank will have to re-cycle, and you may experience what’s called New Tank Syndrome.

      In any case, feed sparingly and avoid any big water changes. Your tank needs a chance to balance and any big changes will only delay that balancing. With time, the water should clear up on its own. If the problem persists, add Algone to your filter.

  8. Ayush sinha says:

    I have made a 20 gallon aquarium before 2 days ago and yesterday when I added water to my aquarium the water remains cloudy. I have very less amount of gravels they are unclear. I have cleared the gravel but water remains hazy and I have only 2 fish, one red cap and koi carf, they also have produced lots of waste in this new aquarium. Please help me to remove cloudy water.

    • Scott @ Algone
      Scott @ Algone says:

      The cloudy aquarium water is likely just particles from the gravel that haven’t yet settled, or you are already experiencing a bacterial bloom. A bacterial bloom is caused by an imbalance of nitrifying bacteria in the fish tank. This is not unusual for a new aquarium. Avoid any big changes such as large water changes, or the addition of any new fish at this time. This should clear up as the aquarium establishes a healthy biological balance. Also see ‘New Tank Syndrome‘ for more information.

  9. Mahdi says:

    This changes has Influence in my red cherry shrimp tank. Temperature, Ph and hardness is good for these Nitrate & Ammonia is low but i dont konw what happend in my tank 🤔

  10. Lorene Whittington says:

    My aquarium has turned yellowish color I’ve done 3 water changes plus added water conditioner and bacteria I still can’t get my tank to clear I had my water tested and my levels are all out of whack nitrates we’re 200 I have never had a problem with my tank until I added new stones I did wash them really well so I don’t know what to do other than take all my fish out and start over any suggestions

  11. Tabitha kirkhart says:

    My 28 gal nano cube has been set up with seahorses since november it went through its cycle very well. Has been pretty clear water the entire time but have been having a problen with film algea on my sand. I bought 2 small sand sifting starfish and a horshoe crab to help with the algea almost a month ago. It has been doing very well until yesterday when i came home my pumps were low on water and were kind of blowing out a bunch of small bubbles. I did a cleaning of my ornaments and sand only about 15% water change. Today i woke up to a very cloudy tank. I tested my peramiters were all good nothing out of the ordinary. Im not sure why it is cloudy except for a theory of my horshoe crab mixing my sand up so much the milky powdery water may be coming from the bottem. Will it hurt my seahorses? And how can i get rid of it and have crystal clear water without using additives to the water to do so?

    • Thilo
      Thilo says:

      Fine air bubbles can cloud the water, residues in the pump and pipes can have the same effect. Fine particles from the substrate is also an option. In any case, it should not persist for long and the water should return to normal.
      Other possibilities is a bacteria bloom.
      Bacteria are settling inside the filter in larger numbers than outside. If the filter water volume is reduced, some of the bacteria might no be working properly, or become dormant. Watch for possible ammonia spike.
      In addition and in consequence, waste is not processed efficiently and heterotrophic bacteria (the ones processing decaying organic material) can grow rapidly, and this is was turns the water cloudy.

      In case of a bacteria bloom, reduce feeding, increase oxygen, and increase the frequency of water changes/ gravel cleaning, not exceeding 10% weekly.

  12. Willie says:

    I set up a new aquarium. But I use some black& white gravel from a former tank. And few fish after it was two week up. Any way water turn pea green. Took my water to be tested was told given some Prime that detoxification the water. Later did 20% water change that didn’t help . So I Broke the tank down completely was everything throughout clean. Had a very clean tank. Now starting with my 3 fish out of 7 when I first started. Put the necessary water regiments for the water. By 2 week it is right back and I more fish I lost. Now I really want to redo it again. It seems so hard to keep this aquarium pretty.Can that black & white gravel be the problem? Please your opinion?????

    • Thilo
      Thilo says:

      When you start an aquarium, the system will cycle. This in short means that bacteria settle to make the water safe for the fish. This also means that waste is not properly processed, and that waste can cause the water to turn green or white. This has little to do with the gravel selection.
      When starting, keep the filters running, and make sure the water is well oxygenated. If you have fish, feed very sparingly. Make sure you follow a rigid regiment in maintenance.

  13. Bethany says:

    First off all when I put the cycling stuff in the tank it was cloudy but only for a day or two. But now it’s got like a cloudy substance on the top of the water just floating is this meant to happen? If so why? How long will it last?

    • Scott @ Algone
      Scott @ Algone says:

      You’re best off contacting the manufacturer of the cycling product you used in the tank. They should be able to help you determine any side effects and further actions you can take.

    • Victor says:

      Hello mate. That “Stuff” it’s just bio-film. Completely normal. Just use your filter to “wave” the surface of the water and you should be fine!

  14. Cassie says:

    We started our new 10 gallon tank on Saturday. We purchased a 24 hour quick start conditioner, washed all of our decorations, gravel, etc. and set up the tank. 24 hours later we introduced 3 Mollies; woke up the next morning with 3 deceased fish and cloudy water. I’ve read about the bacteria bloom and figured I must have introduced the fish too soon to the tank. We ordered a bubbler to help oxygenate the water but we don’t know if we should install it now or wait until after the bloom has cleared? How long should we wait to introduce the fish? We’re devastated and have told our 3 year old that the fish had to go to the doctor … any help is greatly appreciated!

    • Thilo
      Thilo says:

      Every aquarium needs to cycle, you can read more in detail using the following link:
      In short, bacteria need to settle in order to make the aquarium safe for fish. This process can take 2-4 weeks to complete. During this time you will see spikes in ammonia/ nitrite, both can be fatal for the fish. Once both values return to 0 ppm with nitrates measurable, the cycle is complete, and you can add the fish of your preference.
      To start the cycle you can use the no fish method https://www.algone.com/cycling-the-aquarium-without-fish or use starter fish (feeder fish)

    • Terri P says:

      Even though Mollies are listed under “beginner” fish, the are too susceptible to water condition changes. Some good old male guppies, danios, or tetras would be better choices.

  15. Jeffrey Cagle says:

    I broke down my 10 gallon tank yesterday and cleaned everything with a strong bleach solution because my betta died of fin rot. I set it back up and it crystal clear. I added a small amount of gravel from an established tank with an undergravel filter to seed the fresh one with good bacteria. I also stuck a cotton swab in ammonia and swirled it in the water. This morning, the water was cloudy…GOOD! That means my tank is growing beneficial bacteria. The bacteria will settle into the gravel and filter in a few days. The water will clear and my tank will be on it’s way to sustain fish soon.

  16. Jack says:

    Hi I am very new to the fish hobby it is for my little girl , I set the tank up 2 days ago and not knowing nothing about fish I put 6 glow light tetra , 3 mollies (balloon) and 2 golden barbs none have died but my water has gone really cloudy (white) I have read up on this and it could be the start of the cycle I am going to buy a API freshwater master test kit but I want to know if there is anything I can do to help these fish they seem to be opening and closing there mouth fast but no clamped fins can someone please give me some pointers on how I can keep them as healthy as possible during this cycling process the tank it 57 litres I don’t know water parameters I till I get lit tomorrow

    • Scott @ Algone
      Scott @ Algone says:

      Hello Jack, your options are limited here. The white cloudiness generally is not harmful for the fish unless it’s a bacterial bloom, which can significantly de-oxygenate the fish tank. To avoid this, make sure there’s enough surface agitation fro the filter return. The ripples and splashing, as water return to the tank, is what introduces oxygen for your fish to breath. Usually this is a real concern if fish are gasping for air at the water surface.

      Also, avoid overfeeding. This is the single biggest mistake beginners make. We recommend feeding only once daily, and sparingly at that. Fish have a slow metabolism and simply don’t require the amount of food often recommended. Food, eaten or uneaten, is what builds up organic waste in the tank, leading to all sorts of other problems such as high nitrate, green water, and algae outbreaks.

      Lastly, if things don’t go well and your water doesn’t clear up as quickly as you wish, resist making big changes at once. Aquariums are delicate closed-looped eco-systems which fare much better with small incremental changes. Changing too much water for example, will disturb beneficial bacteria needed for a healthy aquarium.

      I hope this helps. Please use our search feature at the top of the page, or the ‘Aquarium Articles’ drop-down menu to access a wealth of free aquarium resources published right here at algone.com.

    • Angel says:

      Hi Jack,

      In the future, it’s best to introduce fish slowly to a tank to establish good bacteria. A lot of pet stores will tell you to “filter your empty aquarium for a week” but if there is no catalyst, all you’re doing is moving water around (PS: I’m one of those pet stores by the way, heh)
      I tell new aquarists to set up their tank, let it filter to settle any debris down for 24 hours or so and for the temperature to become stable. Then start with what many will call “garbage fish” (I hate that, because as far as I’m concerned no fish is garbage). Glow lights are great but neons, I’ve experienced, are a bit hardier. start with 5 of them, and wait a week, then add more fish slowly, one at a time. Adding fish that much and that quickly can crash your system.

      It sounds to me like they may be stressed, so I would turn off the light for longer stretched as a time. The light is more for us than them anyway. Also, look into adding an air stone. I always have one in my tanks, with the exception of my saltwater tanks.

      As Scot with Algone said, be careful in changing too much of your water at one time. No more than 30% at any given time. With water changes comes PH changes and that alone can be dangerous.

      Also as Scott said (Im starting to like this Scott gentleman! :P) feeding sparingly. A fish’s digestive system is nothing like ours. It is much less complex and over feeding causes waste. Waste causes ammonia, and ammonia is bad. I prefer feeding my fish (both fresh and saltwater) frozen foods such as brine shrimp, mysis shrimp and daphnia. Lots of protein and helps keep the water clearer than flaked.

      I hope this helps.

  17. Jason says:

    My tank is a love fish panorama 40!! Its 37ltrs and came with a filter and thermostat and lights as a kit! I have 3 male swordtails 5 neon tetra and 2 plecs

  18. Adam says:

    Hi iv set up a new tank it’s day two and it’s seems to be fluctuating in clarity. I don’t know whether this is a bacteria bloom or the substrate needing to settle I have two air stones and a water skimmer wich is keeping the tank oxygenated. I have planted the aquarium in a sand and soil substrate. My PH levels are fine and my nitrates levels are 0 but my ammonia is high around a light green. Any suggestions? I don’t want to start a water change as I want the fillters to build up healthy bacteria

    • Scott @ Algone
      Scott @ Algone says:

      This just sounds like it’s going through the normal paces of establishing the nitrogen cycle. Keep an eye on the ammonia which should only be detectable for a short period, followed by nitrite, and eventually the less toxic nitrate. Check these articles, The Nitrogen Cycle & Biological Aquarium Filtration, for more on the topic.

      It’s ok do do small water changes of 10 – 15% every 4 or 5 days, during cycling, to relieve some of the stress caused by nutrients. Again, keep an eye on that ammonia. This should not be detectable for more then a few days while establishing a new fish tank. Once it is no longer detectable, you know you’re on your way to a balanced aquarium.

  19. talan richards says:

    Hi my fish tank has water has been cloudy for a year. I empty half the water and nothing helps I’ve emptied it completely, the water will stay clean for about 3 days then goes cloudy again. Could it be the tank itself or the pump?

    • Matthew says:

      Don’t empty the water. The cloudiness is resulted by the fishes bacteria. Read up on the nitrogen cycle. It will really help because doing 100% water changes result in looking all your good bacteria and can kill the fish because of ammonia spikes

    • Jeffrey Cagle says:

      Good bacteria will float around in the tank until they settle to the bottom and stick to objects. If you use a water clarifyer, it works by making small particles stick together so the filter can grab them…but the particles are then sticky in general. They will also stick to the inside of the tank glass making to tank appear cloudier than it really is. I’m a strong believer in water clarifiers. But you may need more often interior glass cleaning. Make sure you get a glass cleaner from an aquarium store. Sponges bought from supermarkets contain chemicals to keep the sponges soft when you buy them that are toxic to fish.

    • Charlie Figura says:

      Hi – I’ve a similar problem as talan. I’ve got a 46 gallon tank that’s been established for about three years, but I’ve been fighting cloudiness, occasional algae blooms, and diatoms/brown algae for about a year. API master test kids indicate ph is 7.4, NH3 is 0, Nitrites 0, nitrates 20-30ppm. I tested my tap today and found that the tap is sitting at 20-30ppm. This is a *lightly* planted tank, I don’t want to invest in more plants until I can get the diatoms under control! I have about 16 fish (all tetras) all told, and feed them once every two-three days to avoid overfeeding.

      I do 25% to 50% water changes one to two times a week. I’ve tried going a week without water changes, and all that happens is that the diatoms take over EVERYTHING. I’m … a bit at my wits end, because everyone talks about cloudiness as a *temporary* thing.

      I’d LOVE some help here. 🙁

      • Thilo
        Thilo says:

        The main ingredient is silicates and the most common mistake is to scrape the algae off the glass. This simply helps them to distribute themselves literally all over. To start, check silicates and use a silicate remover. Other things on the check list are, light (is there to much), water flow (increase water flow), hard water, and nitrates. You might need to pre-treat your water, or switch to an alternate water source if the water is too hard.

  20. Ella says:

    Hello! I haven’t rinsed my gravel and ages and I woke up to a milky tanks. I’m assuming it’s bacteria do show up I clean the gravel and then add half a tank of new water? I have to go to school first and I’m scared my Oscar will die

    • Thilo
      Thilo says:

      It is bacteria and keeping good maintenance will prevent the bacteria bloom. This bloom is triggered by an excess of waste that needs to be processed by the bacteria. If there is more waste to process the bacteria will grow, sometimes at a rate that turns the water cloudy.
      Make sure the water surface is disturbed (waves) by adjusting the filter outlet. This will make sure the oxygen levels are not getting too low. Also make sure to vacuum the gravel as you do a water change. Watch out for ammonia.

  21. danielle says:

    How long should a new tank stay cloudy for after adding conditioner and bacteria starter and etc…? Its been about 4 days since i set up my tank.

    • Scott @ Algone
      Scott @ Algone says:

      It various from tank to tank. But generally a bacterial bloom should clear up on its own within a week or so. It’s important not too make any big changes during this time… large water changes, adding a bunch of new fish… and don’t overfeed as this creates added waste and pollutants in the aquarium. For the white cloudiness to clear up, the aquarium has to naturally balance between waste generated and nitrifying bacteria. Any big changes during this balancing process will only delay establishing the nitrogen cycle.

  22. John miles says:

    PLEASE HELP !!!!
    got a fish tank we clean it out and by the 3rd day it is cloudy?
    We all so have clean the gravel out too but it still goes cloudy by the 3rd day.
    WE all so have got a filter aswell in the tank but the filter should last about a mouth or so?
    Just wanted to know what Eles there is what we could do 2STOP the fishtank
    From getting cloudy.

    • Thilo
      Thilo says:

      Water conditioners containing bacteria or bacteria supplements/ nutrients can cause cloudy water. Poor water circulation, or environmental aspects such as debris or hard water can do the same.

  23. Gail says:

    Dear Thilo, Help!
    My 5 year old tank has turned milky white and I can’t correct it.
    65 gallon freshwater with two very big goldfish one has been in there 5 years, the other about 3 years.
    Fluval 404 canister filter.
    More than a month ago I cleaned the gravel pretty good and also I think my pump was failing over the last month so I replaced it. Chemistry tests that all is in balance.
    Tried some ‘clear magic’ two weeks ago but it only cleared it up a little.
    I keep reading and being told by fish store it is a bacterial bloom and to just wait it out but it is not getting any better and it has been at least 5 weeks of messing around, water changes etc.

    I appreciate any advice you have.
    I have

    • Thilo
      Thilo says:

      No need to mess with the problem. Large or frequent water changes often worsen the situation. Best way is to maintain your regular maintenance schedule, reduce the amount of food you feed and feed that every other day. Reduce the temperature a few degrees and increase the water flow at the surface to ensure higher oxygen levels. The clear magic is likely a flocculant, it clumps together small particles. It does not work on bacteria, for that you need a water clarifier 🙂

  24. Sal HERESI says:

    I have a 125 gallon tank for freshwater fish. I started it 2 weeks ago . I added 1 table spoon per 10-gallon. Which was 25 table spoons of tropical freshwater water salt. 3 days larer I added 20 goldfish to start the build of bacteria. I have 2 filters aqua clear 110. And seachem 110. Its been 14 days and now my tank is,a little cloudy. What am I doing wrong? I want to start adding but,afraid the tank is not ready. The temperature is 78. 80 degrees

    • Thilo
      Thilo says:

      You are not necessarily doing anything wrong. In some cases the bacteria build up is so rapid that it discolors the water whitish. Bacteria use up oxygen, so you must make sure the oxygen levels are adequate. The sign to watch out for is fish gasping at the surface. Increase the water movement on the water surface by adjusting the filter outlet, this will increase the oxygen levels.

  25. mataya says:

    two of my new half gal aquariums that i just got one conditioned with nutrafin betta plus and the other with top fin water conditioner neither of them decorated had the fish in there for three days and both have milky white cloudy growths all through the water in patches i was wondering if you knew what happened?

    • Thilo
      Thilo says:

      Could be some residue in the aquarium or gravel, which the filter will eventually take care of. High nutrient water from the store (the bags you brought the fish home with). Water conditioners can also cause a temporary discoloration of the water, espescially those that bind small particles to clumps (the fallout is what you can see as white haze), or conditioners that contain bacteria/ bacteria starters.

  26. Lucy says:

    Hello! I wonder if you could help me. On Saturday I set up my Aqua first time fishkeeper tank. I cleaned out the tank, the gravel, and the plant I have in there. However in the package, there was no pump. I phoned up the shop and asked if we could still put the water in as it has to be in there 7 days before I add any fish and they said its fine to put the water in. That day the water started to get dark and cloudy but I just assumed it was because there was no pump to filter the water. I got my pump yesterday and got it all working but it’s gotten worse. It’s gotten even more cloudy. I’ve been adding in the conditioner and the bio boost as recommended yet it’s still very cloudy. I’m not sure what to do. I am planning on getting my fish between Friday – Monday but I’m not sure if I have to re fill my tank see if that helps due to the fact I had no pump to begin with or keep that water and hope for the best. Please help me.

    • Thilo
      Thilo says:

      The discoloration could be due to unwashed gravel or the plant soil. Starting over would be best in this case. Just drain the water rinse out the gravel and re-fill. I would not recommend the plant, there are substrate and light conditions to be met for the plant to thrive. Keep it for later once you got more comfortable with the aquarium.

      I would strongly recommend that you familiarize yourself with the cycle (link below). This is an essential part in setting up an aquarium. Keep things simple and always follow through with maintenance.


    • Colton Price says:

      You have to start your tank off with a filter because when you put bacteria in you need that bacteria to be cycled through the filter.

  27. Melanie says:


    We just started a new tank yesterday. No fish are added yet but we do have a couple of java ferns.

    I rinsed out the tank, the gravel, rinsed all the filter parts. Used aquarium conditioner, some bacterial supplement and some formula called easy care which says it balances chemistry, pH and alkalinity.

    We have added no fish or food or anything else. The filter has been running for almost 24 hours now. The tank is very milky/cloudy. The lights are a warm colour, so it looks yellowish.

    Any ideas of what to do?

    • Thilo
      Thilo says:

      Bacterial supplements can, and in your case did, cause a whitish discoloration of the water. Do keep in mind that your water chemistry will change once you add life to the aquarium. Right now, you are testing and treating tap water. My recommendation would be to familiarize yourself with cycling of an aquarium. This will help you a great deal in successfully setting up and maintaining an aquarium.

    • DAVID HICKS says:

      I have had my aquarium set up for about 4 weeks. I had to add P.H. drops because the P.H.was low! I added 1 tea spoon of baking soda to my 20 gall.tank because the P.H. was still low! I had the water tested and alkaline was not rite. I had to add alkaline drops and after that the water turned milky ! What should i do?

    • Thilo
      Thilo says:

      This is quite temporary and can quickly be corrected by using activated carbon. A yellowish discoloration indicates tannin. In case the discoloration in more on the white side, then it is likely caused by the addition of bacteria. Please familiarize yourself with the cycle to avoid any shortfalls. Bring patience.

  28. Martin Novak says:

    I have identical five gallon tanks that I’ve run for nearly ten years. I say they are identical, because the contents are the same for both, as is the filtration. Recently, one tank has developed a tendency to a milky bacterial bloom each time I feed. Chemical testing shows 0 ppm for both ammonia and nitrites, and 30 ppm for nitrates. The fish are hardly overcrowded: until today, the tank housed a single neon tetra and a catfish. I feed once daily and minimize the amount of food. Both tanks are filtered with three-stage AquaClear filters and follow a regular maintenance schedule. (I’m so anal that I maintain a spreadsheet to track maintenance. Everything is the same for both tanks, yet one tank is crystal clear, and the other is perpetually cloudy. I’m out of ideas. Do you have any?

    • Thilo
      Thilo says:

      No two aquariums are alike, you can get close, but that will be as good as it gets.

      There are multiple biological and chemical reactions that make up the environment. These changes might be subtle but widen in the long run. Some affects are not immediate and will present themselves when they are least expected. There are many factors including even the fish behavior. Digestive system, some eat more some less which can cause more or less of one substance to be created. Everything triggers something.
      We have info on cloudy tanks readily available on our site, and it will provide you with the remedies you need.

  29. Jenn says:

    Put my new filter on in September was ok until , needed changing , started with bubbles and noise. The hob filter was sitting both for month , then just restarted both of them knew needed then, new one only giving me issues .

  30. Jerry Brown says:

    I set up my aquarium about 1 month ago. I put the water in with just filters for about 2 weeks. Then I added cycles and fish. It has been about 4 weeks now and I still have a slightly cloudy tank but I am now losing fish left and right. I have tested my water along with 3 independent dealers and ALL shows safe water levels. I added a canister filter thinking not enough filtration but no luck. I am running 2 Penguin 400’s along with a Marineland C530 canister filter. I have lost Angel fish, Tetras, Bala Sharks, and Iridescent Sharks. Any ideas are greatly appreciated. I really don’t wanna lose my entire tank. Everything I added fish I added stress coat. I also added a little aquarium salt per the dealers to try.

    • Thilo
      Thilo says:

      If all the water parameters are within acceptable limits, the next step would be to check on any signs of disease. Check the bodies of the fish, observe them to see if they are acting strange or unusual. Eating habits, any outside signs such as ulcers, inflamed gills, check the skin, fins eyes, and so on.

    • Chris says:

      If you haven’t figured out the problem by now all the fish may be gone but I have just stumbled over this thread and wanted to add something requarding the aquarium salt, I’m not sure if the problems started before or after adding salt or if you use it regularly and have been adding more when the dealer said to? That might be the problem of loosing your fish is to much salt in the aquarium for a freshwater setup. Salt doesn’t evaporate. Only way for salt to be removed is several water changes. I’ve read that another person was told the same as you and was using salt as recommended regularly. But she took the wording from the LFS the wrong way and was adding a small amount of salt daily as a remedy but having that much salt killed of the rest of her fish.

  31. Diane says:

    so Sunday (it’s now Tuesday) I walked into my living room and my 3 yr old niece was by my 10 gallon fish tank. It was extremely cloudy (greenish). She said she fed them and I believe it was a couple table spoons and shes pretty good about ratting on herself so I do not think anything else was added. But in the case that there was something else added I took all the fish out and moved them to another 10 gallon tank. Deep cleaned all gravel, heater, decor, air stone, filter, and changed the filter cartridge. I placed everything into new tank with fish. Gravel I waited until Monday after making sure it was very clean. I now have somewhat white, smokey, cloudy water. Water levels are all good.. So whats the deal?? HELP

    • Scott @ Algone
      Scott @ Algone says:

      Hello! When you basically did a whole tank cleaning you disturbed the nitrifying/beneficial bacteria which are needed for the healthy biological balance of your aquarium. The white water is likely a bacterial bloom which should clear up on its own as the tank comes back into balance. Your aquarium is probably re-establishing the nitrogen cycle.

      Just feed the fish minimally and avoid changing more then 10 – 15% of the water at a time. If the white cloudiness persist you can also use Algone to clear it up.

      • Scott @ Algone
        Scott @ Algone says:

        If the filter is running as it should, the tank will likely clear up on its own shortly. Likely you are experiencing a bacterial bloom which is quite common during the break-in of a new fish tank. Please be sure not to feed your fish too much food. Sparingly, once a day should help balance the tank. Too much food is the number 1 source of pollution and waste in the aquarium. Also avoid performing large water changes in hopes of solving the cloudy water issue. This will further disturb the balance of the tank resulting in a delay of the break-in.

  32. Luke says:

    Hi my Name is Luke and this is the second five gallon aquarium I have had. I have A Fluval chi and one betta. i have been through alot. So please Stay with Me… When I bought The tank I had a betta and an african dwarf frog. And then i got a neon tetra the water never went throught this cloudy stuff at the begging. then algea started growing on the inside of the tank so bieng dumb but reading online they said water changes and a sponge also the gravel was dirty. Anyway I did a 100% water change and killed my neon tetra and my adf died of a disease few days before. Then I got a dwarf gourami and a algea eater (i know major overstock) so The next day i gave both those fish away and got a guppy(wich suprisingly got along with my betta) and then I did a gravel vacuum 75% water change and killed the guppy. So know i have one betta. Know the cloudy Water is back and I tried api accuclear which says clears water instantly but 12hrs later water got cloudier. so i will re apli, what do i do. And the weird thing is i was 7 when i had my first 5 gal fish tank and it never got cloudy. Please help.

    • Thilo @ Algone
      Thilo @ Algone says:

      Small aquariums can be more tricky than larger ones. The whitish water indicates a bacteria bloom. Bacteria use up oxygen. Before and during the bloom, you might experience higher elevations of ammonia/ nitrite.

      Changing 75 – 100% of the water dramatically changes the environment of the fish. That includes pH levels and other vital parameters. You should never do such a large water change. Excessive cleaning can decimate the bacteria colonies.

      In your case, cloudy water indicates that the bacteria colonies are repopulating, growing at rates that turns the water cloudy. For the benefit of the bacteria, you should be patient and leave the cycling of the aquarium as nature intended without interference at this point. Monitor the aquarium for ammonia/ nitrite/ nitrate. Once the first two values read out at 0 ppm, and nitrates are detectable, the cycle is complete and you can start with corrective measures if needed.

  33. FishAddict says:

    Ok so, my tests came out where it is supposed to be just right for my mollies. I do not have overstock unless ssomene lied to me about how many gallons my free fish tank is… I did measure it with my measuring tape app.
    My tests always come put right.
    This couldnt be true.. Except i have been pufting in warm water for my cold aquarium. And i have a heater. So everytime i have a cloudy tank my fish cannot breathe. Its the second time too. Blah

    • Thilo @ Algone
      Thilo @ Algone says:

      Cloudy milky water is a bacteria bloom, and bacteria need oxygen. In severe cases of cloudiness oxygen can get depleted to the point where it becomes dangerous for the fish. In any case, if you can provide sufficient oxygen to the water by means of the filter, the fish will be just fine. Take it as a precaution.

      Bacteria blooms often occur with the water parameters quite in range. Reasons include overfeeding, using water conditioners with added bacteria, high biological load (plants, fish and other organisms) lack of maintenance (cleaning the gravel) medication, and sometimes it just happens if the bacteria are disturbed.

  34. maryjane mckenrick says:

    Please help, I cannot clear the water in my saltwater tank, andbut I don’t want to quit!!!I am losing all my fish, I have tried everything I’ve read…PLEASE HELP I don’t want to lose them all…aND it’s costing me a fortune…b

    • Scott @ Algone
      Scott @ Algone says:

      So sorry to hear you are experiencing fish loss. I assume the aquarium is newly setup? If this is the case you should read about ‘new tank syndrome‘. Cloudy water itself is rarely a threat to fish life. It’s the underlying nutrients that spike that can become lethal.

      You should test your water for ammonia and nitrite. Both precede the more commonly known nitrate and are the result of waste breaking down in the aquarium. Ammonia and nitrite are quite lethal if fish are exposed to them for prolonged periods. They inflame the fish’s gills and make it difficult for them to breath.

      If either ammonia or nitrite are present in the water, I would recommend cutting back on feeding to once every other day. And sparingly at that. This will be a temporary situation and your fish will not starve due to this. The idea is to limit new waste entering the fish tank. Waste eventually breaks down into these problem nutrients. 10 – 15% water changes every 3 – 4 days should also help bring down these toxic nutrients. A well balanced tank will only have detectable nitrate, but never ammonia or nitrite. Beneficial bacteria aka nitrifying bacteria need to establish in sufficient amounts in the tank to successfully break down waste into the less toxic nitrate. This bacteria is usually lacking in new aquariums or tanks that have gone through significant changes. Introducing several new fish, large water changes, a breakdown and complete cleaning of the aquarium, an overstocked or overfed fish tank, all can be the reason for a bacteria imbalance.

      Here are a few links with some info that may be helpful:

      Nitrifying Bacteria
      The Nitrogen Cycle
      Aquarium Ammonia
      Aquarium Nitrite

      Also check out Algone. It clear cloudy water AND removes excess nutrients from the aquarium.

  35. jamie says:

    What is the white build up on my fish tank i have not yet put any fish in due to it because it looks a bit like fine skin?how could I prevent this

    • Scott @ Algone
      Scott @ Algone says:

      It may be some fungus or mold buildup if it’s growing on the gravel and/or glass. This is usually not a threat to fish life but you should remove it just to be safe. Fungus/mold feed on organic waste in the tank. Even though there are no fish in your tank, the substrate may have contained sufficient organic matter to cause this.

      White cloudy water, as outlined in the article above generally indicates a bacterial bloom. Click here for tips on clearing cloudy aquarium water.

  36. Kip Jordy says:

    Virtually all pet stores have crystal clear water. How do they manage it?

    I have tested the water from PetSmart, PetLand, and WalMart. All three of them have 0 chlorine, 0 ammonia, a hardness of about 100, and a pH of about 8.4 (quite high). My tanks have a lot more ammonia and a lower pH (and my tanks are at best a bit hazy – never crystal clear).

    • Scott @ Algone
      Scott @ Algone says:

      Pet stores usually run all of their aquariums via a shared filtration system. This means they have a much larger water volume then meets the eye. The greater the volume of water, the easier it is to maintain as it is far more forgiving and more difficult to throw out of balance.

      As far as your tanks, you should never have detectable ammonia unless you just set up the aquarium. Ammonia inflames the gills of fish and makes it difficult for them to breath. It is quite lethal if fish are exposed to it for a prolonged period. Further, the pH should have no bearings on hazy water.

      You can use Algone to reduce ammonia, nitrite and nitrate. Algone also polishes the water crystal clear.

      Detectable ammonia in the aquarium indicates some type of imbalance with the nitrifying bacteria. This can be caused by accumulating waste in the tank (overfeeding), changing too much water too frequently, adding new fish, overstocking the tank, failure to keep up with maintenance. Basically anything that causes a dramatic change in the aquarium’s overall bio-load or causes tank conditions to deteriorate.

  37. ericB says:

    I recently bought a 150 gallon tank .off a friend and I decided to go with sand instead of gravel..I also bought a fake coral piece from petsmart I filled the tank up and it’s been setting a week and all the sudden it’s milky white ..I wanted to run it for a whole before I put any agressive stock in it ….CAN ANY ONE HELP WITH THIS NOT SURE WHAT TO DO ITS ALREADY SETUP

    • Scott @ Algone
      Scott @ Algone says:

      You are likely experiencing a bacterial bloom which is not uncommon after initial setup of an aquarium. Beneficial bacteria establish during the first weeks of a newly set up fish tank and white cloudiness can result due to an over abundance of this bacteria. In most cases this will clear up on its own as the tank balances. The only potential treat of a bacterial bloom is the (remote) possibility of de-oxygenation of the aquarium since the bacteria uses oxygen. For this to become a threat to fish is an extremely rare event and very unlikely to happen.

      It;s best to side on the side of caution however and test the water for ammonia and nitrite before interdicting fish. Both are lethal to fish if exposed to high levels over extended time. It is normal to have ammonia and nitrite spikes during the cycling of the fish tank. Once established (usually 4 – 6 weeks) both should be undetectable and only far less harmful nitrate should be measurable in small to moderate amounts.

  38. Thilo @ Algone
    Thilo @ Algone says:

    Cloudy water does not just have one single cause. It is a variety of excess waste that triggers the water to turn cloudy. Algone removes a variety of substances that will help clear the water, but it is the total amount of this waste that determines the time frame. In addition, it always helps to minimize the feeding and to consider supporting measures such as increased maintenance.

    Additives such as water conditioners containing bacteria, or anything similar, should be discontinued until the water clears back up again. Water changes should not exceed 10% per week.

    Lastly, and for the majority of the cases, the water clears up literally overnight. A gradual or visible improvement is rarely observed. Once the excess waste is below a certain threshold, the water clears.

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